Powerful Typhoon Hagibis on Saturday claimed its first victim even before making landfall, as potentially record-breaking rains and high winds sparked evacuation orders for more than 1.6 million people.
Rated "large and very strong", the storm has also forced the cancellation of two Rugby World Cup matches, disrupted the Japanese Grand Prix and grounded more than 1,600 flights.
It is forecast to crash into land in central or eastern Japan early Saturday evening, packing maximum gusts of 216 kilometres per hour (134 miles per hour) Japan's Meteorological Agency (JMA) said.
But hours before the worst of the storm arrived, its outer bands claimed a first casualty in Chiba, east of Tokyo, which was also badly hit by a powerful typhoon last month.
"A 49-year-old man was found in a toppled mini truck. He was sent to hospital but confirmed dead," Hiroki Yashiro, a spokesman at Ichihara Fire Department, in Chiba, told AFP.
Hagibis is forecast to be the first storm rated "very strong" to hit the main island of Honshu since 1991, when the category system was introduced, local media said.
By midday, 1.64 million people in the affected area were under non-mandatory evacuation orders, with authorities urging the elderly, disabled and those with children to leave early.
Hagibis is an unusually large storm, expected to bring "brutal winds and violent seas" to large swathes of the country, the weather agency said.
The expected rainfall, in particular, has sparked concern, with the JMA warning that high tides ahead of a full moon increase the risk of flooding.
It has issued warnings for strong winds, high waves, landslides and serious flooding for large areas of Honshu.
- Power outages -
With the centre of the storm still hundreds of kilometres away in the Pacific, torrential rain was falling and tornado-like gusts of wind ripped into several homes in Chiba, destroying one.
Five people including a three-year-old boy were sent to hospital, but none suffered serious injuries, the local fire department told AFP.
The JMA has forecast half a metre of rain for the Tokyo area in the 24 hours to midday on Sunday, with more for the central Tokai region.
Television footage showed gigantic waves smashing into coastal breakwaters and residents living near a river in Tokyo piling up sandbags in front of their houses.
Others have nailed wooden boards to the frames of windows.
By 9:00am local time (0000GMT) 11,600 households in Chiba had already lost power. The region was badly hit by another powerful typhoon in September.
Automakers, including Toyota and Honda, have shut down their factories, and many supermarkets and convenience stores in the capital closed, a day after residents shopping for typhoon supplies emptied the shelves.
- Rugby, F1 disrupted -
The storm has also thrown two major sporting events into disarray, delaying Japanese Grand Prix qualifiers scheduled for Saturday and forcing the cancellation of two Rugby World Cup matches: England-France and New Zealand-Italy.
The storm could also jeopardise a key match-up between Scotland and Japan on Sunday. Officials are not expected to make a final decision on that game until Sunday morning, after they have assessed any damage to the venue and transport links.
Scotland face elimination if the match is axed and have warned they could take legal action if the game is cancelled. World Rugby called the threat "disappointing".
The storm is also causing transport chaos over a long weekend in Japan.
Japanese airlines have scrapped more than 1,660 domestic flights and some 260 international flights on Saturday, NHK said.
Many bullet train lines from the capital are suspended, along with both overground and some subway lines serving the Tokyo area.
The storm has also forced the first all-day typhoon closure of Tokyo's Disneyland and DisneySea theme parks, with doors shut from Saturday until at least noon on Sunday.
Japan is hit by around 20 typhoons a year, though the capital is not usually badly affected.
Hagibis is bearing down on the region just weeks after another powerful storm, Typhoon Faxai, hit the area with similar strength, killing two and causing major damage in Chiba.
More than 36,000 homes were damaged or destroyed in Chiba, and the local government has urged those in affected buildings to take shelter elsewhere during the storm.